Ventricular arrhythmia in patients with acute myocarditis: A cohort study

Patients with acute myocarditis (AM) are at increased risk of arrhythmias.

We aimed to characterize the timing and potential predictors associated with ventricular arrhythmias (VA).

A total of 351 consecutive patients hospitalized with AM on the intensive care unit with continuous monitoring between 2000-2023 were included into a retrospective cohort study. We analyzed predictors, temporal occurrence and different forms of VA in patients with AM.

Mean age was 41.3 years and 74.4 % were men. Overall, 45 VA occurred in 36 (10.3 %) patients: 26 (58 %) non-sustained ventricular tachycardia (VT), 10 (22 %) sustained VT, 6 (13 %) cardiac arrest and 3 (7 %) ventricular fibrillation. The majority of VA (79 %) occurred within the first 24 h, but 11.9 % occurred only after 72 h. Among the analyzed variables cardiac troponin T (cTnT), left ventricular ejection fraction (LVEF), syncope at presentation and female sex were independent predictors for VA. A combined model including these four variables showed good discrimination, with an area under the curve of 0.80. Compared to patients without VA, patients with VA more often received advanced therapies (30.6 vs 5.7 %, p < 0.001), and experienced a higher rate of incident or worsening heart failure (52.8 vs 16.5 %, p < 0.001) and increased mortality (19.4 vs 0.3 %, p < 0.001).

In patients with AM, VA occur in 1 out of ten patients, most often manifested within the first 24 h. A model including cTnT, LVEF, syncope and female sex performed well in predicting VA.